Why are public opinion polls failing?

In 2014 in Scotland's independence referendum, most British polls showed independence losing in a close race – in fact, it was lost overwhelmingly 55.7% to 44.3%. In 2015, Prime Minister David Cameron won a stunning victory at a time when polls suggested his chances of winning were, at best, very slim.

Cameron then was fooled into believing that a Brexit poll would back his stance that the UK should remain in the European Union. False opinion polls suggesting Brexit was unpopular and that voters wanted the UK to stay in the union were decisively wrong and cost him the premiership.

And opinion polls that showed that Prime Minister Theresa May would win the UK general election this year in a canter were also horribly wrong and she came within a whisker of being defeated by Jeremy Corbyn's Labour Party. She lost 13 seats and the Conservative majority, Corbyn won an extra 31 seats and now May has to rely on the Northern Ireland's DUP for confidence and supply.

In France, opinion polls ahead of the 2017 presidential election showed the top three candidates in contention but none of these made it through to the runoff between Emmanuel Macron (who won) and Marine Le Pen.

French opinion polls were so badly wrong that the leading newspaper La Parisienne took a break from writing stories based on polling results.

Pollsters in France excused the woeful results of their polls by saying that only 12 percent had confidence in political parties and were voting all over the place. How do they know that? Why public opinion polls of course.

You would have to feel sorry for outgoing President Francois Hollande who decided not to seek a second term because of poor public opinion results. Perhaps, just maybe, he was panicked by some false polls.

Kevin Rudd who liked to present himself as a man of inflexible principle once candidly admitted:

Of course I base all of my election promises and policies on opinion polls.

Perhaps that is why he ultimately lost so badly.

Mind you, that's just my opinion.